code: def sys_normalized_adjacency(adj):
      adj = sp.coo_matrix(adj)
      row_sum = np.array(adj.sum(1))
      row_sum = (row_sum == 0) * 1 + row_sum
      d_inv_sqrt = np.power(row_sum, -0.5).flatten()
      d_inv_sqrt[np.isinf(d_inv_sqrt)] = 0.0
      d_mat_inv_sqrt = sp.diags(d_inv_sqrt)
      return d_mat_inv_sqrt.dot(adj).dot(d_mat_inv_sqrt).tocoo()
  
file_path: PGL/examples/chebnetii/ogb/processing.py
imports: import numpy
  import torch
  import pickle
  import argparse
  from ogb.nodeproppred.dataset_pyg import PygNodePropPredDataset
  import scipy.sparse
  from torch_geometric.utils import to_undirected
  from torch_sparse import SparseTensor
label_desc: Use image node_id 1 for calling a global function with example usage: sys_normalized_adjacency(adj) and returns: d_mat_inv_sqrt